go/pkg/mod/golang.org/x/[email protected]/go/packages/external.go

type driverRequest …

// findExternalDriver returns the file path of a tool that supplies
// the build system package structure, or "" if not found."
// If GOPACKAGESDRIVER is set in the environment findExternalTool returns its
// value, otherwise it searches for a binary named gopackagesdriver on the PATH.
func findExternalDriver(cfg *Config) driver { … }